Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental Quality
Part 5 - Underground Storage Tank Regulations
Chapter 2 - Mississippi Commission on Environmental Quality Underground Storage Tanks Regulations Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST) (Adopted March 22, 1989; Amended August 25, 2011, Last Amended August 23, 2018)
Appendix 11-5-2-280.4 - GUIDELINES FOR THE PERMANENT CLOSURE OF PETROLEUM UNDERGROUND STORAGE TANK SYSTEMS
Section 11-5-2-280.4-4 - SAMPLING LOCATIONS FOR TANKS
Section 11-5-2-280.4-4.1 - General Requirements
The goal of sampling a tank excavation at closure is to represent the contamination which may exist in a manner that is as accurate as possible while at the same time minimizing the number of samples that are necessary to achieve the stated purpose. Although the sampling locations described in this document are the minimum necessary, they are not intended to substitute for the conditions which may exist at a particular location. Therefore, a certain amount of professional judgement is necessary in order to evaluate and properly assess the site conditions at a tank closure.
When conducting sampling at a tank removal, all backfill materials must be removed from the excavation prior to sampling. Whether sampling the sidewalls or the floor of an excavation, all samples must be collected from a depth of at least one foot into the native soil. Soil samples shall be collected immediately after the removal of all backfill material. When closing tanks in place, the soil borings must be conducted in the native soil immediately surrounding the tank bed excavation. Soil samples shall be collected immediately after completion of the soil boring.
No compositing of samples (including sampling of the backfill) is allowed and each sample that is collected must be analyzed separately.
If "true" groundwater (refer to Section 3.2) is encountered during excavation activities, a groundwater sample must be collected from the excavation. No soil sampling is required if a groundwater sample is collected unless soil contamination is evident. Any soils that appear to be contaminated must be sampled in addition to sampling of the groundwater. Follow the soil sampling requirements as described in Sections 5-7 of this document when soil sampling is necessary.
